A chemical vapor deposition process is carried out in a reactor chamber having a set of plural parallel ion shower grids that divide the chamber into an upper ion generation region and a lower process region, each of the ion shower grids having plural orifices in mutual registration from grid to grid, each orifice being oriented in a non-parallel direction relative to a surface plane of the respective ion shower grid. A workpiece is placed in the process region, so that a workpiece surface of the workpiece is generally facing a surface plane of the nearest one of the ion shower grids, and a gas mixture comprising a deposition precursor species is furnished into the ion generation region. The process region is evacuated at an evacuation rate sufficient to create a pressure drop across the plural ion shower grids between the ion generation and process regions whereby the pressure in the ion generation region is several times the pressure in the process region. The process further includes applying plasma source power to generate a plasma of the deposition precursor species in the ion generation region and applying successive grid potentials to successive ones of the grids.